Banned PCBs still present in population, affecting brain function after four decades

Polychlorinated biphenyl compounds (PCBs) were banned in the US about three decades ago, but the negative effects of these chemical compounds continue to show up in seniors.

Maryse Bouchard, a researcher from the University of Montreal and CHU Sainte-Justine, has made a significant association between high PCB exposure and lower cognitive abilities in seniors aged 70 to 84 years. Bouchard reports, “While most studies have looked at the impact of PCBs on infant development, our research shows that this toxin might affect us throughout our lives.”

PCBs phased out decades ago, but still lurking in individuals
For over 40 years, the production of PCBs has been phased out of manufacturing, but this hasn’t stopped the chemicals from lingering around, especially in seniors. In the study from the University of Montreal, PCBs were still found lingering in the blood of all individuals studied. In the study, 708 Americans’ blood samples were collected to determine the levels of toxins in their bodies. The participants completed a memory and motor skills test to determine their cognitive performance in the presence of PCBs.

PCB levels were pervasive in the participants’ blood. Even levels generally considered safe, posing low risk, were associated with cognitive deficits in the elder participants.

Bouchard summed up the results, “Aging persons could be at particular risk because of higher cumulative exposure built up across a lifetime, susceptibility due to underlying medical conditions, such as vascular disorders, and diminished cognitive reserve capacity.”

Since PCBs accumulate in the lipid tissues of mammals and marine life, they can spread throughout the food chain. With their ability to spread and reside in animal cells, PCBs have made a home in the cells of human populations.

PCBs were mass produced by Monsanto, the infamous genetic seed engineer
PCBs were once thought of as safe, as many chemicals compounds are believed to be today. As Monsanto took over commercial production of PCBs in 1929, use expanded in the manufacture of flexible PVC coatings and electrical components. As the electrical industry took off decades ago, PCBs were used commercially in coolants and insulating fluids for transformers and capacitors.

Used as stabilizing additives and for heat resistance, PCBs possessed a wide range of uses. Monsanto, who marketed PCBs under the trade name Aroclor up until 1977, began phasing out production of the toxin as awareness grew of PCB’s terrible health effects and as the Stockholm Convention outlawed the compounds globally.

PCBs destroy cognitive performance, alter brain function
An Environmental Health News report goes into further detail on how PCBs affect brain function. A study from the Netherlands points to the ability of PCBs to manipulate brain signals. In the study, specific PCB compounds were found to increase the signalling power of a specific brain chemical which normally “squelches nerve messages.”

GABA, the chemical responsible for halting specific brain signals between nerves, is enhanced in the presence of PCBs. The alteration of these chemical pathways in the brain interfere with the communication of neurons. This could affect a person’s behavior and their ability to perform motor skills related tasks.

The Netherlands study examined PCB’s effect on human post-synaptic neurons. While most PCB research has focused on changes in the presynaptic neuron, this study went further. After injecting DNA for the human GABA receptor into eggs from African clawed frogs, the scientists mixed the GABA DNA with mixtures of different PCBs, allowing them to study the effects of select PCBs on the human GABA receptor.

The results showed that specific PCB compounds enhanced the ability of GABA DNA to stop brain signals. This was witnessed through the increased level of normal electrical current generated when GABA binds to its receptor.

Since PCBs can store in human cells throughout a lifetime, the brain signals of seniors can be altered in drastic ways, affecting their cognitive performance as they age.